If you're able to make a tea or extract - at least make the tea. Hehe, even that is still rough on the stomach the first few hours, ime. Even with tea I would get pretty intense cramps for the first 3 or so hours, along with a bit of nausea, eventually subsiding.

Id imagine eating straight cactus to be pretty rough on the stomach. Tea would be a better option, as long as you have water and some time to cook it.

Bloating and cramping don't sound too enjoyable.